The present disclosure relates generally to the field of submerged combustion furnaces and methods of use thereof to produce molten glass, and more specifically to methods and systems for monitoring glass and/or glass foam density as a function of vertical position within a vessel downstream of a submerged combustion melter.
A submerged combustion melter (SCM) may be employed to melt glass batch materials to produce molten glass by passing oxygen, oxygen-enriched mixtures, or air along with a liquid or gaseous fuel, or particulate fuel in the glass batch, directly into a molten pool of glass usually through burners submerged in a glass melt pool. The introduction of high flow rates of products of combustion of the oxidant and fuel into the molten glass, and the expansion of the gases cause rapid melting of the glass batch and much turbulence, and possibly foaming.
Molten glass produced by an SCM is typically about 30 percent void fraction with small bubbles evenly distributed throughout the molten mass of glass. These are referred to herein as “entrained bubbles.” This void fraction is much higher than molten glass produced by traditional, non-submerged combustion melters. When molten glass contains a large amount of bubbles, or has a layer of foam floating on top, or both of these conditions exist, it can be extremely difficult to ascertain the local and bulk distribution (size and/or location) of bubbles within the molten glass, and therefore the local and bulk glass density and/or glass foam density, with existing level or depth measuring techniques. When this determination cannot be made accurately, less efficient operation of glass refining equipment and/or the submerged combustion melter may result. For example, if the distribution of bubbles is not known with great confidence, it must be assumed other hand, if the amount and/or distribution of bubbles in the molten glass is underestimated, the resulting glass may be “underlined” and need to be reprocessed, or at worst, discarded as waste.
At least for these reasons, it would be an advance in the glass manufacturing art using melters if density and/or density gradient of the molten glass and/or glass foam produced during melting of glass-forming materials could be monitored in melters and/or equipment downstream of glass melters, in particular submerged combustion melters and equipment downstream thereof. Monitoring density of the molten glass and/or glass foam may also allow new or revised control schemes for the melter itself, and/or the equipment downstream of the melter.